The subject matter of the present invention is an improvement in water filtering devices attached to faucets for domestic use.
It has long been proposed that water faucets, such as household water faucets, restaurant, office and other drinking water outlets, be equipped with a water filtering device such that the householder or other user can assure the potability of the water withdrawn from the faucet for drinking or cooking purposes. As far back as 1906 there issued to G. Klumpp U.S. Pat. No. 818,264 disclosing such a device, and in the meantime numerous patents have issued disclosing variations for such devices. However, the fundamental difficulty has been that such filtering device, in order to be practical, must on the one hand effectively filter the water to significantly increase its potability while yet, on the other hand, have a sufficiently long efficient filtering life so as not to require almost constant replacement. Moreover, the devices heretofore proposed have failed to meet a further requisite, namely, that the device be compact, simple of construction and hence economical and be aesthetically pleasing so as to be accepted and used by the consumer.
The problem has been compounded by the fact that as the years have gone by the standards for what would be considered potable water have greatly increased. With the higher the standards has come a greater demand that the filtering devices have a greater filtering efficiency. Accordingly, it has been all the more difficult to attain a relatively long efficient filtering life for the device at a sufficiently low cost so as to render the device economically feasible for the householder or other user. In essence, then, there is need for a water filtering device for attachment to a faucet which at one and the same time provides potable water to today's high standards for potable water, and on a cost basis which is easily within the budget of the average householder.
There are basically four types of drinking water purification systems for home kitchen faucets at present.
An end-of-tap device is designed to fit entirely onto the end of the kitchen faucet. A flow diverter is first screwed onto the faucet followed by a purification chamber filled with active media. When the flow diverter is activated, the water flow is diverted into the purification chamber and purified water is delivered to the sink, either back through the diverter or directly out of the chamber. Typically, pressure drop is built into the system by mechanical restrictions, and the flow is controlled to slow rates. The advantages of the end-of-tap devices are low cost and simple installation. The disadvantages are mechanical limitation to the purification chamber and poor aesthetics.
A counter-top device is essentially a large end-of-tap device and is plumbed the same way. The only difference is that the purification chamber is mounted on the counter top and is connected to the diverter valve with hoses. The water can return to the sink via a separate faucet (integral with the device) or back to the diverter through a second hose. The counter-top device allows for larger canisters, but still has an aesthetic problem. Installation is simple, and cost is moderate.
Third faucet devices are mounted under the sink where there is room to fit even larger purification chambers for more efficient purification. Aesthetics are significantly improved. Water is fed to the purification chamber from a tee mounted in the faucet supply. The purified water is then returned to the sink via an added ("third") faucet. Integral flow restrictors are included to throttle down to low flow for excellent purification capability due to the ability to mount larger systems under the sink. However, the third faucet results in higher cost, more difficult installation, and (to a lesser extent) an aesthetic problem.
In addition, one disadvantage associated with all of the above units is that the water is stagnant in the purification chamber, except when drinking water is desired. If left for extended periods, there is potential to grow bacteria. Manufacturers of all devices deal with this problem by instructing the consumer to flush the device for several minutes if left unused for extended periods.
In-line devices are also mounted under the sink where larger purification chambers can be utilized. These chambers are similar to third faucet systems, however, the plumbing is different. All of the water from the supply line is plumbed directly into the purification chamber and water flow discharges to the sink via the main kitchen faucet. No internal flow restrictors are used, and it is left to the consumer to adjust the flow to achieve good purification. The main advantages of this system is lower cost and simplified installation (compared to third faucet systems) as well as limited stagnation time (compared to all other systems). The main disadvantage is that flow control is subjectively left to the consumer, therefore, extent of purification is uncontrolled. A disadvantage which is consequent to the fact that flow control is subjectively left to the consumer manifests itself in certification testing of purification devices. Thus, the end of tap, counter top and third faucet devices have internal flow restrictors which reduce the flow of water through the filtering device. In-line devices do not have these flow restrictions. Testing protocol does not allow for consumer adjustment of flow through in-line devices such that the unrestricted flow through the filtering device is not sufficient to provide sufficient contamination removal. Thus, although certain in-line devices have excellent removal efficiency upon controlling the flow of water through the device such as made by the end user, such devices may not be certified since the end use flow control is not allowed during testing.
It is an object of the present invention to provide improvements in in-line filter systems for domestic water sources.
It is a further object of this invention to provide improvements in in-line filter systems for domestic water source which maintain the advantages of the in-line system and at the same time removes the subject control of filter efficiency presently placed on the end user.